Color kinescope mounting assembly for shifting shadow mask during thermal expansion



1968 J. w. SCHWARTZ ETAL 3,399,319

COLOR KINESCOPE MOUNTING ASSEMBLY FOR SHIFTING SHADOW MASK DURING THERMAL EXPANSION Filed Oct. 18, 1966 INVENTORS James W. Schwartz BY Loszlo Jcvonk @awww, Jim 7%, BMWZGALLAW ATTORNEYS United States Patent 015cc Patented Aug. 27, 1968 COLOR KINESCOPE MOUNTING ASSEMBLY FOR SHIFTING SHADOW MASK DURING THERMAL EXPANSION James W. Schwartz, Western Springs, and Laszlo Javorik, Chicago, 111., assignors to National Video (lorporation, Chicago, 111., a corporation of Illinois Filed Oct. 18, 1966, Ser. No. 587,530 I 10 Claims. (Cl. '313-8 ABSTRACT OF THE DISCLOSURE A shadow mask is mounted within a colortelevision tube adjacent the viewing screen for correcting misregistration due to thermal expansion of the mask relative to the screen as the mask is heated by impinging electron beams. Each mounting assembly includes a connector adapted to be fitted on supporting posts embedded in .the flanges of the faceplate panel and rigid, curved member fastened to the clip and to the frame of the shadow mask at two separate locations defining a plane generally parallel to the plane of the mask. The rigid member has a coefficient of thermal expansion different from that of the shadow mask, and when the shadow mask is heated, the uneven expansion causes the curved member to straighten out thereby shifting the shadow mask axially of the tube and closer to the viewing screen for correcting misregistration.

This invention relates to a color television tube mask mounting and, more particularly, to a mounting adapted to substantially compensate for the thermal-shift of the mask openings during operation. This application is related to the co-pending application of James W. Schwartz et al., Ser. No. 554,106, filed May 31, 1966.

The instant invention goes beyond the disclosure in the above-identified application and compensates for the thermal expansion of the mask by moving the mask axially to maintain register of the mask openings with the path of electrons from the guns to the phosphor dots, and the provision of a novel connection between the mask and the in terior of the envelope of the cathode ray tube for this purpose constitutes a principal objective of the invention.

Other objects and advantages may be seen in the details of construction and operation set down in this specification.

The invention is described in conjunction with an illustrative embodiment in the accompanying drawing, in which:

FIG. 1 is a fragmentary elevational view of the faceplate portion of a rectangular color television tube, with the above-mentioned mask mounted in place;

FIG. 2 is a sectional view, taken transversely through the face plate of the television tube, and showing means for mounting the side of the mask, such as would be viewed along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged detail view of a mask side-mounting means;

FIG. 4 is a view similar to FIG. 3 but showing the parts thereof in a different operative condition;

FIG. 5 is a perspective view of a portion of the mask mounting means; and

FIG. 6 is an elevational view of a modified form of mask mounting element.

19--MEADOR (62608)NITE PATS-FRL, AUG. 9

In the illustration given, the numeral 10 designates generally a color television tube of rectangular shape which, for the purpose of clarity, is shown only in the extreme forward end thereof, i.e., the face .plate 11. Provided on the interior front face of the face plate 11 is a phosphor screen 12 which is made up of a plurality of phosphor dots adapted to emit light in red, blue and green colors, respectively, so arranged that one each of the dots, representing red, blue and green fields, can be energized by the first, second and third guns, respectively, provided in the throat of the tube (not shown). The numeral 13 generally designates the mask which consists of a frame 14 and foraminous portion 14a to which the mask is secured as by welding. The frame 14 is equipped with a connector generally designated 15 for supporting the mask within the tube 10. As can be appreciated from a consideration of FIG. 1, mounting connectors of the type designated in 15 in FIG. 2 are seen at the sides in FIG. 1 and a modified version as at 16 is employed for supporting or stabilizing the top of the mask within the tube. Inasmuch as the instant invention has to do only with the portion of the connector 15 which is secured to the mask, the remaining portion of the connector can take a variety of forms, such as those seen in the above-identified application.

The connector 15 as seen, for example, in FIG. 2, is apertured at one end as at 17 for mounting the same on a post 18 provided as part of the interior of the tube 10. Such posts are embedded within the glass tube and serve as anchorages for connectors 15. The connector 15 at its upper end is equipped with an arched spring fitting generally designated 19 and seen best in FIG. 5. The fitting 19 has legs 20 and 21 coupled by an integral cross part 22. The cross part 22 is welded to the member 23 to constitute the connector 15 with the member 23 lying between the legs 20 and 21. Thus, the connector 15 includes the fitting 19, as well as a plate-like body 23, which is the portion equipped with the generally triangular aperture 17 for the receipt of mounting post 18.

Referring again to FIG. 5, it will be seen that each of the legs 21 is equipped at the ends thereof with integral lug portions as at 24, the lug portions 24 being spotwelded as at 25 (see the upper righthand corner of FIG. 3) to the frame 14 associated with the shadow mask 13. Further, each of the legs 20 and 21 is arched or arranged with a generally stepped *arcuate configuration as can be appreciated from a comparison of FIGS. 3 and 5.

The fitting 19 is constructed of a material having a different c-oelficient of thermal expansion from that of the mask 13. For example, the fitting 19 may have a negligible coefiicient of thermal expansion as is the case when it is constructed of Invar while the mask 13 is usually constructed of cold-rolled steel. Alternatively, the fitting 19 can be constructed of material having a substantially higher coeflicient of thermal expansion than that of the material used to fabricate the mask 13.

In the illustration given, the fitting 19 is constructed of a material having a low coeflicient of thermal expansion. The mask frame 14, on the other hand, has a relatively high coefiicient of thermal expansion. Thus, as the frame expands from the condition of FIG. 3 to that of FIG. 4, the fitting 19 is changed in shape as can be appreciated from a comparison of the showings in FIG. 3 and FIG. 4. In other words, the degree or height of the arch of the legs 20 and 21 is reduced with the consequent movement of the mask frame 14 toward the screen 12 (compare the dimension x in FIG. 3 with the dimension x in FIG. 4)-

By moving the shadow mask 13 toward the screen 12, the lateral displacement of a given opening 26 in the screen 12 is compensated for 'and thus the opening 26 is again in register with the electron beam and the particular group of phosphor dots to be activated by that beam.

In FIG. 6, the connector is again apertured as at 117 for mounting on post 118. However, two fittings 119 119' are employed, oppositely oriented so as to give difiereutial movement to the connector 115 and thus pivot it about the post 118 as well as translating the mask axially.

. 3 Each fitting I19 and 119' has a lug 127 projecting away from the member 123 and into the mask frame to provide a stable three-point support.

The terms arched and arcuate are used interchangeably herein. It will be appreciated that under some circumstances the legs 20 and 21 can advantageously have sides that are true arcs with the cross-piece 22 being secured to complete the arcs as contrasted to the chordal configuration shown. In some other instances it may be advantageous to construct the device from a single piece, as'where the welds 127 are eliminated from FIG. 6.

While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of illustration, many variations in the details hereingiven may be made by those skilled in the art without departing from the spirit and scope of the invention.

We claim:

1. In a relatively elongated color television tube having an enlarged end with mask mounting posts extending inwardly at the enlarged end of said tube, a mask positioned in said tube adjacent said enlarged end, and means connecting said posts 'and corresponding portions of said mask, said means including at least a portion constructed of a material having a coefiicient of thermal expansion ditferent from that of said mask, said portion having an arched configuration and connected to said mask at two points spaced apart on said arched portion whereby expansion of said mask upon temperature increase thereof, tends to change the height of said arched portion and thereby move said mask axially of said tube.

2. The structure of claim 1 in which said means is connected to said mask at 'at least three points.

3. The structure of claim 1 in which said means is a unitary piece of metal.

4. The structure of claim 3 in which said metal has a negligible coefiicient of thermal expansion.

5. A color television tube comprising an elongated envelope having a viewing screen at one end, a shadow mask in said envelope adjacent to said screen, and mounting means for mounting said shadow mask in said tube, said mounting means including a member having a different coefiicient of thermal expansion than said mask and defining first and second spaced-apart portions fastened to said mask, and means for coupling said member to said envelope, whereby said mounting means is adapted to translate said mask when said mask is heated.

6. The structure of claim 5 wherein said member is arched and has a' lower coefiicient of thermal expansion than said mask thereby tending to straighten out as said mask is heated.

7. The structure of claim 5 wherein said member has a higher coeflicient of thermal expansion than said mask thereby tending to become curved as said mask is heated.

8. The structure of claim 5 wherein said mounting means further comprises a second member similar to said first member connected to said coupling means and defining first and second portions fastened to said mask and adapted to translate said mask when the same is heated, and wherein each of said first and second members is arched and said coupling means is connected to both of said members.

9. The structure of claim 8 wherein said arched members are similarly-oriented relative to said screen and said fastened portions of said members define planes generally perpendicular to the axis of said tube.

10. A color television tube comprising an elongated envelope having a viewing screen at one end, a shadow mask in said envelope adjacent said screen, and means mounting said mask in said tube, said means having first and second arch members oppositely-oriented relative to said screen and each including first and second portions attached to said mask and further including coupling means for connecting said members to said envelope whereby said means is adapted to pivot and translate said mask relative to said screen upon temperature change within said tube.

References Cited UNITED STATES PATENTS 2,795,718 6/1957 Van Hekken et al. 313- 92 X 2,961,560 11/1960 Fyler 313-64 2,755,405 7/1956 Wilhelm 3l3-92 JAMES W. LAWRENCE, Primary Examiner. V. LAFRANCHI, Assistant Examiner. 

